Conventionally, polyamide fibers, having strength, wear resistance, and dyeability superior to other synthetic fibers, have been efficiently used in various fields. However, clothing manufactured using polyamide fabric is disadvantageous because it readily wrinkles and does not sufficiently recover its original shape after washing or when worn. The wrinkling of the clothing is affected by various structural factors, including the molecular shapes of polymer, the number of twists, the density and thickness of cloth, and the external environment, including temperature and humidity.
In order to prevent the polyamide fabric from wrinkling due to such various factors, useful resins processing methods, including acid or alkali treatment or shrink proofing, chemical treatment methods, including ageing or annealing, and physical methods including mix spinning. However, acid or alkali treatment undesirably incurs high damage to cloth, and mix spinning treatment with less wrinkling fibers leads to insufficient anti-wrinkle effects.
Accordingly, attempts to develop shape memory fibers, which do not generate deformation or wrinkling after washing and do not readily wrinkle during wearing, are being made these days. The shape memory fiber is characterized in that it does not easily wrinkle and easily recovers its original shape. Thus, even though the shape memory fiber wrinkles, it may manually spread flat to thus easily recover its original shape, and furthermore, exhibits high durability upon ironing or washing.
As shape memory cloth, Japanese Unexamined Patent Publication No. Sho. 61-252353 discloses a nonwoven fabric sheet composed of a shape memory resin fiber and a shape memory resin adhesive. However, because such a nonwoven fabric sheet is formed by bonding short fibers with an adhesive, it is thick and uneven and is liable to incur high production costs due to the use of the adhesive. Further, as the shape memory fiber, shape memory polyester or polyethyleneterephthalate fibers have been introduced, but shape memory polyamide fibers or fabrics have not yet been developed. Therefore, it is urgently required to develop a high-functionality polyamide fabric having shape memory properties and the advantages of polyamide fibers.